Hello Joecel i do not know if this is gonna help you but just for this case the circle it is over defined because you are applying 2 constrains to 2 lines that already have a dimension (i assume that the arrow at the right its a dimension simbol), so the radius of your circle will be the same that the value of that dimension, and you use another dimension, the diameter dimension, so the program is using 2 dimension for the same entity, if you want to repair this, you can remove one constraint or remove the diameter dimension from the circle, i hope this was helpful for you, if it was please click the answered button.